Ochratoxins in Wines: A Review of Their Occurrence in the Last Decade, Toxicity, and Exposure Risk in Humans

Ochratoxins (OTs) are mycotoxins frequently found in wines, and their contamination can occur during any stage of the winemaking process. Ochratoxin A (OTA) has been the most widely reported and the only one whose concentrations are legislated in this beverage. However, ochratoxin B, ochratoxin A methyl ester, ochratoxin B methyl ester, ochratoxin A ethyl ester, ochratoxin B ethyl ester, ochratoxin α, ochratoxin β, OTα methyl ester, OTA ethyl amide, and OTA glucose ester have also been reported in wines. Thus, detecting only OTA would lead to the underestimation of ochratoxin levels, which is a risk to human health. Considering the threat represented by the presence of ochratoxins in wines and the long-term health problems that they can cause in wine drinkers, this paper aims to review reports of the last 10 years regarding the presence of different ochratoxins in wines and how the winemaking process influences the degree of contamination, mainly by OTA. Additionally, toxicity from human exposure due to the consumption of contaminated wines is addressed.

Determination of Ochratoxin A and Ochratoxin B in Archived Tokaj Wines (Vintage 1959–2017) Using On-Line Solid Phase Extraction Coupled to Liquid Chromatography

According to the EU legislation, ochratoxin A contamination is controlled in wines. Tokaj wine is a special type of sweet wine produced from botrytized grapes infected by “noble rot” Botrytis cinerea. Although a high contamination was reported in sweet wines and noble rot grapes could be susceptible to coinfection with other fungi, including ochratoxigenic species, no screening of Tokaj wines for mycotoxin contamination has been carried out so far. Therefore, we developed an analytical method for the determination of ochratoxin A (OTA) and ochratoxin B (OTB) involving online SPE coupled to HPLC-FD using column switching to achieve the fast and sensitive control of mycotoxin contamination. The method was validated with recoveries ranging from 91.6% to 99.1% with an RSD less than 2%. The limits of quantification were 0.1 and 0.2 µg L−1 for OTA and OTB, respectively. The total analysis time of the online SPE-HPLC-FD method was a mere 6 min. This high throughput enables routine analysis. Finally, we carried out an extensive investigation of the ochratoxin contamination in 59 Slovak Tokaj wines of 1959–2017 vintage. Only a few positives were detected. The OTA content in most of the checked wines did not exceed the EU maximum tolerable limit of 2 µg L−1, indicating a good quality of winegrowing and storing.

Probing the Interactions of Ochratoxin B, Ochratoxin C, Patulin, Deoxynivalenol, and T-2 Toxin with Human Serum Albumin

Ochratoxins, patulin, deoxynivalenol, and T-2 toxin are mycotoxins, and common contaminants in food and drinks. Human serum albumin (HSA) forms complexes with certain mycotoxins. Since HSA can affect the toxicokinetics of bound ligand molecules, the potential interactions of ochratoxin B (OTB), ochratoxin C (OTC), patulin, deoxynivalenol, and T-2 toxin with HSA were examined, employing spectroscopic (fluorescence, UV, and circular dichroism) and ultrafiltration techniques. Furthermore, the influence of albumin on the cytotoxicity of these xenobiotics was also evaluated in cell experiments. Fluorescence studies showed the formation of highly stable OTB–HSA and OTC–HSA complexes. Furthermore, fluorescence quenching and circular dichroism measurements suggest weak or no interaction of patulin, deoxynivalenol, and T-2 toxin with HSA. In ultrafiltration studies, OTB and OTC strongly displaced the Sudlow’s site I ligand warfarin, while other mycotoxins tested did not affect either the albumin binding of warfarin or naproxen. The presence of HSA significantly decreased or even abolished the OTB- and OTC-induced cytotoxicity in cell experiments; however, the toxic impacts of patulin, deoxynivalenol, and T-2 toxin were not affected by HSA. In summary, the complex formation of OTB and OTC with albumin is relevant, whereas the interactions of patulin, deoxynivalenol, and T-2 toxin with HSA may have low toxicological importance.

Determination of Ochratoxin A (OTA), Ochratoxin B (OTB), T-2, and HT-2 Toxins in Wheat Grains, Wheat Flour, and Bread in Lebanon by LC-MS/MS

Cereals are prone to fungal infection during growth, harvesting, transportation, and/or storage. As a result, cereals such as wheat grains and wheat-derived products may be contaminated with mycotoxins leading to acute and chronic health exposure. The current study investigated the presence of the mycotoxins: ochratoxin A (OTA), ochratoxin B (OTB), T-2, and HT-2 toxins in samples of wheat grains (n = 50), wheat flour (n = 50), and bread (n = 37) from the main mills in Lebanon using LC-MS/MS. Accuracy ranged from 98–100%, recoveries from 93–105%, and intraday and interday precision were 5–7% and 9–12%, respectively. The tested wheat grains, wheat flour, and bread samples did not contain detectable levels of T-2 and HT-2 toxins and OTB. Four wheat flour samples (8% of flour samples) showed positive OTA levels ranging from 0.6–3.4 μg·kg−1 with an arithmetic mean of 1.9 ± 0.2 μg·kg−1. Only one sample contained an OTA concentration greater than the limit set by the European Union (3 μg·kg−1) for wheat-derived products. This study suggests that mycotoxin contamination of wheat grains, wheat flour, and bread in Lebanon is currently not a serious public health concern. However, surveillance strategies and monitoring programs must be routinely implemented to ensure minimal mycotoxin contamination of wheat-based products.

A new preparative method for simultaneous purification of ochratoxin A and ochratoxin B from wheat culture inoculated with Aspergillus ochraceus

Ochratoxins are a mycotoxin family frequently found in agricultural commodities worldwide and pose a potential health risk to humans and animals. To obtain large amounts of high-purity ochratoxins for food safety monitoring and toxicological research, a novel and effective method was established for simultaneous purification of ochratoxin A (OTA) and ochratoxin B (OTB) from a wheat culture inoculated with an ochratoxin-producing Aspergillus strain. The inoculated wheat culture was first extracted with methanol:water (80:20, v/v), followed by one or two cleanup procedures involving acid-assisted liquid-liquid extraction and gel permeation chromatography. Subsequently, target analytes were separated and collected using preparative high performance liquid chromatography. Finally, a combined approach of ultra-high performance liquid chromatography, ultraviolet spectrophotometry and mass spectrometry was applied for purity analysis and structural identification of the obtained toxins. As a result, 100 g of an inoculated wheat culture yielded 69 mg of OTA and 6 mg of OTB with purities greater than 98%. This proposed method might serve as a valuable reference to obtain expensive ochratoxin standards. To the best of our knowledge, this is the first report on simultaneous preparation of OTA and OTB from artificially inoculated wheat culture.